Expandable emboli filter and thrombectomy device

ABSTRACT

Expandable emboli filter and thrombectomy devices adapted for use with microcatheters to remove debris from blood vessels. The devices embody expanded profiles that span the entirety of various sized target vessels and thus are particularly effective in the engagement of debris found in vessels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. Ser. No. 10/397,885, filed on Mar. 26,2003, now abandoned; which is a continuation of Ser. No. 09/768,653,filed Jan. 23, 2001 which issued as U.S. Pat. No. 6,610,077, issued onAug. 26, 2003; the contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention relates generally to filtering and thrombectomydevices and systems which can be used to capture embolic material orthrombi found in blood vessels. The filtering devices and systems of thepresent invention are particularly useful when performing balloonangioplasty, stenting procedures, laser angioplasty or atherectomy incritical vessels where the release of embolic debris into thebloodstream can occlude the flow of oxygenated blood to the brain orother vital organs, which can cause devastating consequences to thepatient. The thrombectomy devices are suited for the removal of thrombusin a variety of vessels. While the embolic filtering and thrombectomydevices and systems of the present invention are particularly useful inthe cerebral vasculature and neurovasculature, the inventions can beused in conjunction with any vascular interventional procedure in whichthere is an embolic risk.

A variety of non-surgical interventional procedures have been developedover the years for opening stenosed or occluded blood vessels in apatient caused by the build up of plaque or other substances on the wallof the blood vessel. Such procedures usually involve the percutaneousintroduction of the interventional device into the lumen of the artery,usually through a catheter. In typical PTA procedures, a guidingcatheter or sheath is percutaneously introduced into the cardiovascularsystem of a patient through the femoral artery and advanced to near thetarget vasculature. A guidewire and a dilatation catheter having aballoon on the distal end are introduced through the guiding catheterwith the guidewire sliding within the dilatation catheter. The guidewireis first advanced out of the guiding catheter into the patient'svasculature and is directed across the arterial lesion. The dilatationcatheter is subsequently advanced over the previously advanced guidewireuntil the dilatation balloon is properly positioned across the arteriallesion. Once in position across the lesion, the expandable balloon isinflated to a predetermined size with a radiopaque liquid at relativelyhigh pressures to radially expand the atherosclerotic plaque of thelesion and thereby dilate the lumen of the artery. The balloon is thendeflated to a small profile so that the dilatation catheter can bewithdrawn from the patient's vasculature and the blood flow resumedthrough the dilated artery. As should be appreciated by those skilled inthe art, while the above-described procedure is typical, it is not theonly method used in angioplasty. Another procedure is laser angioplastywhich utilizes a laser to ablate the stenosis by super heating andvaporizing the deposited plaque. Atherectomy is yet another method oftreating a stenosed blood vessel in which cutting blades are rotated toshave the deposited plaque from the arterial wall. A vacuum catheter isusually used to capture the shaved plaque or thrombus from the bloodstream during this procedure.

In the procedures of the kind referenced above, abrupt reclosure mayoccur or restenosis of the artery may develop over time, which mayrequire another angioplasty procedure, a surgical bypass operation, orsome other method of repairing or strengthening the area. To reduce thelikelihood of the occurrence of abrupt reclosure and to strengthen thearea, a physician can implant an intravascular prosthesis formaintaining vascular patency, commonly known as a stent, inside theartery across the lesion. The stent is crimped tightly onto the balloonportion of the catheter and transported in its delivery diameter throughthe patient's vasculature. At the deployment site, the stent is expandedto a larger diameter, often by inflating the balloon portion of thecatheter.

Prior art stents typically fall into two general categories ofconstruction. The first type of stent is expandable upon application ofa controlled force, as described above, through the inflation of theballoon portion of a dilatation catheter which, upon inflation of theballoon or other expansion means, expands the stent to a larger diameterto be left in place within the artery at the target site. The secondtype of stent is a self-expanding stent formed from, for example, shapememory metals or super-elastic nickel-titanum (NiTi) alloys, which willautomatically expand from a compressed state when the stent is advancedout of the distal end of the delivery catheter into the body lumen. Suchstents manufactured from expandable heat sensitive materials allow forphase transformations of the material to occur, resulting in theexpansion and contraction of the stent.

The above minimally invasive interventional procedures, when successful,avoid the necessity of major surgical operations. However, there is onecommon problem which can become associated with all of these types ofprocedures, namely, the potential release of embolic debris into thebloodstream that can occlude distal vasculature and cause significanthealth problems to the patient. For example, during deployment of astent, it is possible that the metal struts of the stent can cut intothe stenosis and shear off pieces of plaque which become embolic debristhat can travel downstream and lodge somewhere in the patient's vascularsystem. Pieces of plaque material can sometimes dislodge from thestenosis during a balloon angioplasty procedure and become released intothe bloodstream. Additionally, while complete vaporization of plaque isthe intended goal during a laser angioplasty procedure, quite oftenparticles are not fully vaporized and thus enter the bloodstream.Likewise, not all of the emboli created during an atherectomy proceduremay be drawn into the vacuum catheter and, as a result, enter thebloodstream as well.

When any of the above-described procedures are performed in the vesselssupplying blood to the brain, the release of emboli into the circulatorysystem can be extremely dangerous and sometimes fatal to the patient.Naturally occurring debris can also be highly dangerous to a patient.That is, debris which travels through the blood vessel as a naturalresult of bodily functions or disease states and not as a result of anintervention procedure. Debris that is carried by the bloodstream todistal vessels of the brain can cause these cerebral vessels to occlude,resulting in a stroke, and in some cases, death. Therefore, althoughcerebral percutaneous transluminal angioplasty has been performed in thepast, the number of procedures performed has been limited due to thejustifiable fear of causing an embolic stroke should embolic debrisenter the bloodstream and block vital downstream blood passages.

Medical devices have been developed to attempt to deal with the problemcreated when debris or fragments that naturally occur or that enter thecirculatory system following vessel treatment utilizing any one of theabove-identified procedures. One approach which has been attempted isthe cutting of any debris into minute sizes which are unlikely toocclude major vessels within the patient's vasculature. However, it isoften difficult to control the size of the fragments which are formed,and the potential risk of vessel occlusion still exists, making such aprocedure in the carotid arteries a high-risk proposition.

Other techniques which have been developed to address the problem ofremoving embolic debris include the use of catheters with a vacuumsource which provides temporary suction to remove embolic debris fromthe bloodstream. However, as mentioned above, there have beencomplications with such systems since the vacuum catheter may not alwaysremove all of the embolic material from the bloodstream, and a powerfulsuction could injure the patient's vasculature or remove more blood thanis safe. Other techniques which have had some limited success includethe placement of a filter or trap downstream from the treatment site tocapture embolic debris before it reaches the smaller blood vesselsdownstream. However, there have been problems associated withconventional filtering systems. In particular, certain previouslydeveloped filtering devices do not optimize the area for emboliccollection. That is, conventional filtering devices may not present acollection device that spans the entity of the vessel or it may includesupporting structure that itself impedes emboli collection. Certainother devices are not effective when used in conjunction with amicrocatheter.

Moreover, thrombectomy and foreign matter removal devices have beendisclosed in the art. However, such devices have been found to havestructures which are either highly complex or lacking in sufficient oreffective expansion and retraction capabilities. Disadvantagesassociated with the devices having highly complex structure includedifficulty in manufacturability as well as use in conjunction withmicrocatheters. Other less complex devices can pull through clots due toin part the lack of experience in using the same, or lack an adequatelyfine mesh for capturing clots or foreign bodies.

Furthermore, systems heretofore disclosed in the art are generallylimited by size compatibility and the increase in vessel size as theemboli is drawn out from the distal vascular occlusion location to amore proximal location. If the thrombectomy device is too large for thevessel it will not deploy correctly to capture the clot or foreign body,and if too small in diameter it cannot capture thromboembolic materialor foreign bodies across the entire cross section of the blood vessel.Thus, a thrombectomy device that can be expanded to a relatively largediameter from a relatively small diameter is desirable as is the abilityto effectively control such expansion and contraction.

What has been needed is a reliable filtering or thrombectomy device andsystem for use when treating blood vessels. The filter devices should becapable of filtering any naturally occurring embolic debris or thatwhich may be released into the bloodstream during an interventionaltreatment, while minimizing the area occupied by structure supportingthe filter so as to minimally obstruct blood flow, and safely containthe debris until the filtering device is removed from the patient'svasculature. The thrombectomy devices should embody an expanded profilethat completely occupies the vessel at the repair site as well asstructure for effectively expanding and retracting the device. Moreover,such devices should be relatively easy to deliver through amicrocatheter, as well as be deployed and removed from the patient'svasculature and also should be capable of being used in narrow and verydistal vasculature such as the cerebral vasculature. The followinginvention addresses these needs.

SUMMARY OF THE INVENTION

Briefly and in general terms, the present invention is directed towardexpandable devices for repairing blood vessels. The expandable devicesare particularly suited for removing emboli or thrombi from thebloodstream of a human or animal. One significant advantage provided bythe present invention is the potential use of the expandable devices innarrow and very distal vasculature.

In one aspect of the invention, there is provided a loop with an embolicfilter attached thereto. The loop is configured to self-expand generallyperpendicularly to and optionally offset to a longitudinal axis of adelivery catheter. A tether is provided to effect the deployment fromand withdrawal into the delivery catheter. The self-expandable loop andfilter structure advantageously expands to occupy the entirecross-section of the lumen into which it is deployed. When the device isin its expanded configuration, the shape of the loop is defined by thelumen and the tether is positioned near a wall of the lumen.

In another aspect, the present invention includes multiple loops thatare connected by longitudinally extending fibers. The connecting fibersmay be crossing or non-crossing and may terminate at a superior loop orcontinue distally to define a tapered distal end. A catheter is providedfor deploying the double loop device as is a tether which effectuatesthe delivery and withdrawal of the device. The multiple loops areintended to self-expand to occupy the entirety of the cross-section ofthe blood vessel into which it is deployed, the loops assuming thegeometry of the vessel. Additionally, when the device is in its expandedconfiguration, the tether is intended to generally lie adjacent a walldefining the lumen thereby accomplishing less blood flow obstruction.The distal loops may also provide internal support for an embolicfilter, facilitating material entry into the filter.

In a third aspect of the invention, an embolectomy snare is providedwhich has the advantage of being able to assume a very small profilewhen packed within a delivery catheter. The embolectomy snare ischaracterized by including a basket that is formed from non-overlappingelongate members.

In a fourth aspect of the invention, improved expansion control and ameans for optimizing expansion profiles is incorporated into athrombectomy device. In particular, one or more stops are provided on anelongate member to cause a basket-like thrombectomy device configuredcoaxially about the elongate member to thereby open and close thebasket. By varying the weave pattern of the basket of the thrombectomydevice, upon expansion of the same, a concavity can be formed, the samebeing particularly useful for engaging and removing clots from a bloodvessel.

These and other objects and advantages of the invention will becomeapparent from the following more detailed description, when taken inconjunction with the accompanying drawings of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view, partially in cross-section, of anexpandable device of the present invention in its deployedconfiguration;

FIG. 1B is a perspective view, depicting a loop and an expandable devicethat is integral with an elongate member;

FIG. 2A is a perspective view, partially in cross-section, of analternate embodiment of the present invention in its deployedconfiguration;

FIG. 2B is a perspective view, depicting a loop configured withmini-loops for spacing tethers;

FIG. 3 is a perspective view of another embodiment of an expandabledevice of the present invention in its expanded configuration;

FIG. 4A is a perspective view of yet another embodiment of an expandabledevice of the present invention in its expanded configuration;

FIG. 4B is a perspective view, depicting an expandable device of thepresent invention with a medical loop;

FIG. 5A is a side view of an emboli snare of the present invention shownin its expandable state;

FIG. 5B is a cross-sectional view taken along B-B of the device shown inFIG. 5A;

FIG. 6 is a cross-sectional view of the device depicted in FIG. 5A whenwithdrawn within a delivery catheter;

FIG. 7 is a side view of a thrombectomy device of the present inventionshown in its fully contracted configuration;

FIG. 8 is a side view of the device depicted in FIG. 7 advanced distallywith respect to an elongate member;

FIG. 9 is a side view of the device depicted in FIG. 8 which is furtheradvanced distally and placed in an expanded configuration; and

FIG. 10 is a side view of the device depicted in FIG. 9 in its fullyexpanded configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, and particularly to FIG. 1A, there is shownan expandable device 20 of the present invention. The expandable device20 is suited for repairing vessels and in particular, for capturingemboli 22 found in the bloodstream of a patient. Due to its novelstructure, the repair device 20 embodies an expanded profile that ishighly effective in filtering unwanted material from vasculature and iscapable of being deployed within very narrow and distal vasculature,including the cerebral vasculature.

In one presently preferred embodiment, the expandable device 20 includesa loop 24 attached by conventional means to a distal end 26 of anelongate member 28. Attached to the loop 24 is an emboli filter 30. Theloop 24 can be soldered to the elongate member 28 or can be affixedthereto using epoxy or other forms of adhesive. Alternatively, the loop24 can be an integral part of the elongate member 28 (See FIG. 1B). Aband or other mechanical fixation devices (not shown) could also be usedfor this purpose. The emboli filter 30 could be attached to the loop 24using a plurality of proximally extending anchors or fibers 32, each ofwhich are configured into small hoops 34 that engage the loop member 24.

An elongate, tubular catheter 36, preferably a microcatheter orotherwise a lumen of a conventional stent delivery catheter, is alsoprovided. The microcatheter 36 includes an internal bore 38 that isadapted to coaxially and slidably receive the elongate member 28 as wellas the looped member 24 and emboli filter 30 assembly. The deliverycatheter 36 is capable of being manipulated independent of the elongatemember 28 and loop/filter assembly, for example, by holding the deliverycatheter 36 in a particular longitudinal position while advancing theelongate member 28. Alternatively, the delivery catheter 36 can bewithdrawn or advanced while maintaining a desired longitudinal positionof the elongate member 28.

The loop 24 is preferably made from a looped length of superelasticwire. The elongate member 28 can be formed from a guide wire.

Significantly, the loop 24 is configured so that when it exits thedistal end 40 of the delivery catheter 36, the loop 24 projectsgenerally perpendicularly to longitudinal axes of the elongate member 28and catheter 36. It is also contemplated, that for particular purposes,the loop 24 could project at an acute or obtuse angle respecting theelongate member 28. Accordingly, it is contemplated that the loop 21also embodies shape retaining material and a material that permits theloop 24 to quickly and repeatedly return to a desirable pre-formedshape.

It is also highly significant that the loop 24 embodies sufficientflexibility so that upon ejection from the delivery catheter 36, theloop 24 generally conforms to an inside circumference of a blood vessel42 into which it is deployed. In doing so, the elongate member 28 anddistal portion 40 of the delivery catheter 36 are generally positionedadjacent walls 44 defining an interior lumen of the blood vessel 42.Thus, the expandable loop 24 spans the entirety of the circumference ofthe vessel 42. Moreover, the elongate member 28 and delivery catheter 36are advantageously displaced from the center or median of the bloodflow,such that debris traveling through the vessel can avoid these componentsand must pass through the loop 24.

In an alternative embodiment (FIG. 2A), the loop 24 can embody aplurality of members 46, preferably two such members, entwined abouteach other. The twined configuration 46 advantageously embodiesadditional hoop strength without sacrificing the other advantages of theloop configuration such as the ability to assume the contour of theinterior 44 of the blood vessel 42. The twined configuration alsoprovides structure for maintaining a desired spacing between anchors orfibers 32 which are used to attach the filter 32 to the loop 24.Further, rather than relying on an interference fit between the hoops 34and the loop 24 to accomplished desired spacing, the anchors 32 canembody single mini-loops which encircle one of the twined members 46. Inyet another aspect of the invention, the loop 24 can embody mini-loops47 that serve to correctly space the tethers 32 (See FIG. 2B).

The filter 30 includes a proximally directed opening 48 to an interior50. The body 52 of the filter 30 can have any exterior profile but it ispreferred that its exterior generally assume a hemispherical or conicalshape. The fully expanded filter 30 has an opening 48 to the body 52that is generally circular but can be modified for a particularapplication. In one preferred embodiment, the body 52 is made from amesh-fabric material through which blood can readily flow. The meshcontains apertures or pores 54 through which the blood passes but whichare small enough so that debris does not flow therethrough.Alternatively, the filter can embody laser cut mylar or is defined byultrasonically welded polymer fibers. In yet another aspect, the fibercrossing can be bonded with flexible adhesive.

The filter sub-assembly 30 can be made from surgical mesh oralternatively the filter 30 can embody a network of braided members orfibers. For example, the filter can embody a braided expansion wire 50.In one presently preferred embodiment, the expandable device 20 consistsof an elongate member 28 or guidewire with a metal braided basket (notshown) attached to a loop or otherwise directly attached to a superiorend of the wire.

It is additionally contemplated that, as shown in FIG. 3, the weavedbasket 56 may be formed from polypropylene suture 58. In order tomanufacture the weaved basket 56, the polypropylene suture 58 is wrappedin an over and under weaving pattern about a mandrel (not shown) whichcan embody a tapered or straight cylindrical profile. A proximal orinferior end portion 60 includes reversals of direction 62. A distal orsuperior end portion 64 is tied to form a closed structure. The tied endis cut to provide an even profile and a polymide tube 66 having thesmallest diameter possible is placed about the closed end. Thereafter,an adhesive is applied to retain the polymide tubing 66 on the braidedbasket 56.

A shape set loop 24 is then threaded through the reversals 62. By doingso, the braided basket 56 is fixed to the loop 24. In a presentlypreferred embodiment, the polypropylene suture 58 has a diameter of0.003 inches, the polymide tubing 66 has an inner diameter of 0.0318inches and an outer diameter of 0.0364 inches, and the loop 24 is formedfrom 0.003 inch diameter nickel titanium wire.

It is contemplated that in one preferred embodiment the braided basket56 comprises an 8-strand pattern that results in a closed net. Thelength of the basket 56 will vary depending on the size of the materialto be removed. The diameter of the basket 56 will also vary from 2 mm to50 mm depending on the lumen diameter of the vessel from which materialis to be removed. The basket 56 is attached to a loop 24 which opens theproximal end of the basket 51, allowing entry of material into thebasket 56. The loop 24 may be formed of a variety of elastic 24 orsuperelastic materials. The diameter of the loop 24 will match that ofthe basket 56. The loop 24 may be covered, in part or in full, with aplatinum coil to minimize the potentiality of trauma caused by thedevice, and/or to enhance attachment of the basket 56 to the loop 24.The inner diameter of this coil corresponds to the outer diameter of theloop strand, allowing for clearance. A typical coil is 0.009 inches ininner diameter with a wire diameter of 0.0025 inches. The loop 24 isattached to the elongate member 28 via soldering and other joiningtechnology.

The expandable devices 20 advantageously embody a simple structure thatcan assume a very small contracted profile. Thus, the device can be usedin conjunction with a flexible microcatheter 36 that can traverse verynarrow, tortuous and distal vasculature. Upon expansion, theself-expanding loop 24 assumes the contour of the vessel into which itis deployed thereby providing an optimized structure for capturingdebris. Moreover, when the loop 24 is expanded, the microcatheter 36 andelongate member 28 lie adjacent a wall defining vessel and substantiallyout of the way of the flow path. Accordingly, the expandable device 20can be used to effectively repair virtually any portion of a patient'svasculature by simply modifying the range of expanded loop 24 sizes.

Referring now to FIG. 4A, another preferred embodiment of an expandabledevice is shown. In this embodiment, the present invention is embodiedin a dual-looped, expandable device 70. The dual-looped device includesa first or inferior self expanding loop 72, a second or superiorexpanding loop 74, each of which are attached to a distal end of anelongate member or wire 28. Highly flexible connecting fibers 76 arerouted between the first 72 and second 74 loops to thereby define anemboli receiving cavity 78 when the device is in its expandedconfiguration. The connecting fibers 76 act as structure for engagingand capturing emboli and can be cross or non-crossing. Additionally, theconnecting fibers 76 may embody a single continuous fiber or may includemultiple fibers. The fibers may be tied to the second loop 74 or theycan extend (not shown) beyond the second loop 74, tapering off andterminating with a pointed end.

In one preferred embodiment of the dual looped device 70, the elongatemember 28 is comprised of Nitinol and includes a 0.004 inch outerdiameter reduced section for receiving portions of the loops 72, 74.Platinum coils (not shown) are employed to accomplish affixing viasoldering or similar means, the loops 72, 74 to the elongate member 28.The connecting fibers 76 comprise polypropylene strands. Further, in apreferred embodiment, the connecting fibers 76 are routed such thatthere are five (5) points of connection per loop 72, 74, however, few oras many as 10 or more points of connection are contemplated.

The dual-looped device 70 is also contemplated to be used with agenerally tubular delivery catheter 76 that is adapted to slidablyreceive the elongate member 28 as well as receive compressed loops 72,74. The dual-loop device 70 also embodies the advantages associated withthe single loop design. That is, the loops 72, 74 self-expand to assumethe entire contour of a blood vessel into which it is employed in such amanner that the delivery catheter 36 and elongate member 28 lie adjacentto the vessel wall that is substantially out of the flow path. FIG. 4Bdepicts another preferred embodiment in which an additional loop 79between loops 72 and 74 provides support for the filaments, enhancingentry of material to an interior defined by the device.

In use, the expandable devices depicted in FIGS. 1-4 are contemplated tobe packed in a compressed state within the tubular delivery catheter 36.Access is gained to the patient's vasculature via conventional methodsand the delivery catheter/expandable device assembly is placed withinthe patient's vasculature. The assembly is then advanced through thepatient's vasculature to a repair site and the distal end 40 of thedelivery catheter 36 is positioned beyond the repair site. Thereafter,the expandable device 20, 70 is translated longitudinally with respectto the delivery catheter 36 so that the expandable device exits thedistal end of the delivery catheter 36, which in turn, allows theexpandable device 20, 70 to self-expand.

As the expandable device 20, 70 expands, it projects at a generallyperpendicular angle (though any angle is possible) with respect to theelongate member 28 and the loop 24 or loops 72, 74 assume the contour ofthe interior of the vessel of lumen. Moreover, the filter body 52 isopened by the expansion of the loop 24 and in the case of thedual-looped device 70, the expansion of the loops 72, 74 facilitate theformation of the embolic receiving cavity 78.

Once it is in its fully deployed configuration, the expandable devices20, 70 are capable of capturing emboli or other debris travelingantegrade in the bloodstream. The debris enters an opening to the filterbody 52 or the emboli receiving cavity 76 and is captured therein. Oncethe debris is captured, the expandable device 20, 70 may be removed fromthe vasculature, or other means such as a suction device can be employedto independently first remove the debris and thereafter, the expandabledevice can be withdrawn.

With reference to FIG. 5A, there is shown another embodiment of anexpandable device of the present invention which is specifically adaptedfor use as an embolectomy snare device 80. The snare device 80 includesa plurality of shape memory elements 82 that are configured inalternating and generally undulating sections to form a basket structurewhich defines an interior pocket 84 and a proximally directed openingthereto (See FIG. 5B). Adjacent elements 82 on one side of the generallyconical, basket-like profile may be laser welded or fixed to each otherat points of proximity. A proximal end 88 of the shaped memory elements82 is affixed by conventional means to an elongate member 90. Further,the snare device 80 is contemplated to be used in conjunction with agenerally tubular delivery catheter 36 which is adapted to slidablyreceive the elongate member 90 as well as the basket 83 in a compressedconfiguration.

The snare device 80 advantageously embodies elements which arenon-overlapping. To wit, snare device 80 can be packed very tightlywithin an interior 38 of the delivery catheter 36 such as amicrocatheter. This feature is shown in FIG. 6, which depicts across-sectional view of a snare device loaded within the deliverycatheter 36. Due to its ability to be packed into a very small diametermicrocatheter, the snare device 80 is well-suited for use in narrow anddistal vasculature.

In use, the snare device 80 is placed in its compressed state within adelivery catheter 38 that is advanced within vasculature to a repairsite. The snare device 80 is then ejected from a distal end 40 of thedelivery catheter 36 and permitted to self-expand within the targetvessel. The expanded snare device 80 is then brought into engagementwith embolic material found in the bloodstream. The pocket defined bythe basket profile 83 then receives and captures the embolic material,which is then capable of being removed from a patient's vasculature.

It is also to be recognized, however, that the devices described hereincan also be delivered through a guidewire lumen of a balloon or stentcatheter. This allows for direct placement without requiring the use ofa micro-catheter.

Turning now to FIGS. 7-10, there is shown an expandable device 100 whichconcludes an actuating basket 102 defined by elements 103. The elements103 are weaved together in a generally helical fashion. Although thisexpandable basket device 100 is primarily intended for use inthrombectomy procedures, the device has applications to the capture ofemboli in the bloodstream as well. The basket device 100 can be used inconjunction with a microcatheter (not shown) or it can be deployedwithin vasculature without using a microcatheter. As shown in thefigures, the basket device 100 may be attached to a distal end 104 of anelongate, tubular carrier 106.

A retainer 108 is provided at a distal end 110 of the basket device 100.The retainer 108 has a generally cylindrical profile and includes aninternal bore (not shown). The retainer 108 functions to maintain thedistal end 110 of the basket device in a closed configuration both whenthe basket 100 is unexpanded and when it is expanded.

The basket device assembly device 100 is adapted to be slidably placedabout an elongate member 112 in a coaxial arrangement. The elongatemember 112 is likewise received in the retainer 108 in a coaxialarrangement. Elongate member 112 includes a plurality of beads 114, theouter profile which is greater than the internal bore of the retainer108 but smaller than an internal diameter of the elongate tubular member106.

The beads 114 have a dual function. A proximally positioned bead 114 isemployed, as shown in FIG. 7 to retain the basket device 100 in acompressed configuration by holding the proximal bead 114 in engagementwith a proximal side 116 with a retainer 108. Expansion of the basketdevice 100 is achieved by translating the basket device 100 distallywith respect to the elongate member 112 and by causing the distal side118 of the retainer 108 to engage a distally positioned bead 114, thefurther the basket device 100 is translated distally, the greater theradial expansion. Accordingly, the basket device 100 can be controllablyand repeatedly expanded and contracted to the extent desired to engagevessel walls of varied diameters. It is contemplated that the basketdevice 100 embody wire elements 102 which have more stiff distalportions than proximal portions so that when the basket continues toexpand, a concavity 120 is formed. Alternatively, the concavity 120 canbe formed if the basket device 100 is leashed to the elongate tubularmember, for example.

As stated, the basket device 100 can also be used in combination withthe microcatheter. In a first step of use, the microcatheter is employedto deliver an elongate wire 112 which includes only a single bead 114.The microcatheter is then completely withdrawn from a patient'svasculature and a basket device 100 is threaded over the elongate member112. Once the retainer 108 of the basket device 100 is advancedsufficiently to engage the bead 114, the basket device 100 can be madeto expand radially outwardly. In the event use of a microcatheter isessential to the specific application, this alternative approach allowsfor the use of a basket device 100 with an elongate tubular member thathas a larger outer diameter than an inner diameter of the microcatheter,which advantageously allows for increased pushability and columnstrength on the elements 103 defining the basket portion 102.

In view of the foregoing, it is clear that the expandable devices of thepresent invention are useful for the repair of vasculature. Inparticular, the disclosed expandable devices are particularly useful forthe capture of emboli as well as for use in thrombectomy procedures.

It will be apparent from the foregoing that, while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the invention belimited, except by the appended claims.

1. An expandable device for repairing a blood vessel, comprising: anelongate member having a first stop and a second stop positioned distalto the first stop; a generally tubular elongate member positionedcoaxially about the elongate member, the tubular elongate member havinga distal end portion; an expandable basket defined by wire elementsaffixed to the distal end portion, the expandable basket having aterminal end, the wire elements having proximal portions and distalportions, the distal portions being more stiff than the proximalportions; and a slidable member positioned about the elongate member andbetween the first and second stops, the slidable member affixed to theterminal end.
 2. The expandable device of claim 1, wherein the slidablemember has a first end and a second end, the expandable basket beingheld in a compressed configuration when the first end is held in contactwith the first stop.
 3. The expandable device of claim 2, wherein thebasket is expanded when the second end is caused to engage the secondstop.
 4. An expandable device for repairing a blood vessel, comprising:an elongate member having a first stop and a second stop positioneddistal to the first stop; a generally tubular elongate member positionedcoaxially about the elongate member, the tubular elongate member havinga distal end portion; an expandable basket affixed to the distal endportion, the expandable basket having a terminal end; and a slidablemember positioned about the elongate member and between the first andsecond stops, the slidable member affixed to the terminal end, whereinthe basket is defined by helically routed wire elements, the wireelements having proximal and distal portions, the distal portions beingmore stiff than the proximal portions.
 5. The expandable device of claim4, wherein continued expansion of the expandable basket results in aproximally directed concavity.
 6. The expandable device of claim 4,further including at least one leash routed from the expandable basketto the generally tubular elongate member.
 7. The expandable device ofclaim 4, wherein the slidable member has a first end and a second end,the expandable basket being held in a compressed configuration when thefirst end is held in contact with the first stop.
 8. The expandabledevice of claim 7, wherein the expandable basket is expanded when thesecond end is caused to engage the second stop.
 9. An expandable devicefor repairing a blood vessel, comprising: a first elongate member havinga first stop and a second stop positioned distal to the first stop; asecond elongate member having a distal end portion; a plurality ofhelically routed wire elements, the wire elements having proximal anddistal portions, the distal portions having greater stiffness than theproximal portions, the helically routed wire elements forming anexpandable basket affixed to the distal end portion of the secondelongate member, the expandable basket having a terminal end; and aslidable member positioned about the first elongate member and betweenthe first and second stops, the slidable member being affixed to theterminal end of the expandable basket.
 10. The expandable device ofclaim 9, wherein the slidable member has a first end and a second end,the expandable basket being held in a compressed configuration when thefirst end is held in contact with the first stop.
 11. The expandabledevice of claim 10, wherein the expandable basket is expanded when thesecond end is caused to engage the second stop.
 12. The expandabledevice of claim 11, wherein continued expansion of the expandable basketresults in a proximally directed concavity formed by the expandablebasket.
 13. The expandable device of claim 9, further including at leastone leash routed from the expandable basket to the second elongatemember.